Implemented optional data validation

DataStore2/init.lua

@@ -179,13 +179,48 @@ function DataStore:GetTableAsync(default, ...)
 	end)
 end
 
+function DataStore:SetValidator(validator)
+	assert(
+		type(validator) == "function",
+		"function expected, got " .. type(validator)
+	)
+	self.validator = validator
+end
+
+local function AssertValidatorWithDefaultError(validator, input, defaultError)
+    local success, err = pcall(validator, input)
+
+    -- if success but result is false
+    if success and err ~= true then
+        error(defaultError)
+    -- if not success and there is an error message
+    elseif not success and err ~= nil then
+        error(err)
+    end
+end
+
 function DataStore:Set(value, _dontCallOnUpdate)
+	if self.validator then
+		AssertValidatorWithDefaultError(
+			self.validator,
+			value,
+			"Invalid data"
+		)
+	end
 	self.value = clone(value)
 	self:_Update(_dontCallOnUpdate)
 end
 
 function DataStore:Update(updateFunc)
-	self.value = updateFunc(self.value)
+	local updateFuncReturn = updateFunc(self.value)
+	if self.validator then
+		AssertValidatorWithDefaultError(
+			self.validator,
+			updateFuncReturn,
+			"Invalid data"
+		)
+	end
+	self.value = updateFuncReturn
 	self:_Update()
 end